The evolutionary story of the hand

Our fingers can even replace the eyes to perceive the world, as the Dutch paleontologist Volmay can prove this. He has been blind since he was 3 years old. As an expert known for studying marine mussels and their ecosystems, he has never seen fossils. But in the wild, he can perceive the complex morphology and structure of mussels and the rocks on which they are located through the touch of his fingers, and can even “see” many details that have been overlooked by other scientists with his hands. So, how did these functions of human hands evolve?

Hand peculiarities
The human hand is so special not only because it is flexible, but also because it has an extraordinary sensation, it is almost like an independent sensory organ. We can feel the breeze and the temperature of the water with our hands. In the dark, we can insert the key directly into the keyhole, and we can also feel the surface texture of different objects. Some tailors can tell the authenticity of a piece of leather by touching it with their hands without even looking at it.

Open your hand and then close it again; play with your fingers, touch the tips of the remaining four fingers with your thumb; turn your wrist, you should be able to easily rotate it 180 degrees; make your hand into a fist, Put the thumb on the index finger, middle finger and ring finger… For humans, these actions are easy to do, but all apes cannot do it.

In the process of human evolution, the importance of hands can be said to be as important as walking upright. With the evolution of human beings, after being able to walk on two feet, we no longer need to move our bodies with hands. Free hands can be used to do many other things, such as taking food, picking up children, scooping water, collecting materials to build a house, or holding things with one hand and manipulating these things with the other to perform specific tasks. Mission…

For humans, simple actions cannot be done by apes.

Human hands are very dexterous.

The more skilled our ancestors used their hands, the stronger their survivability and the higher the survival rate of their offspring. Therefore, in the process of natural selection, a better hand structure prevails. Our brain and body are evolving simultaneously. In this process, the bones, tendons, muscles and nerves of the hands become more and more coordinated, the sense of touch in the hands becomes more and more acute, and the brain controls the movement of the hands more and more. The more complex it is, the result is that the hand gradually evolves into a “comprehensive tool” that integrates multiple functions such as construction, hunting, feeding assistance, and communication.

Trace to the source
The evolution of the hand can be traced back to 70 million years ago, the ancestor of the primate-the synapse. Early synaptoids were small animals that lived on the ground, and then gradually climbed up the canopy to live, and lived on small insects, seeds and fruits. Being able to grasp small things undoubtedly has an advantage in survival, and the claws of comatose animals have evolved as a result.

For a long time, scientists believed that early hominid animals had a pair of hands similar to modern humans from the beginning. Some fossils found in Africa in the early 1960s can prove this.

The claws of synapses have evolved because they have to go up to trees to grab small foods.

In May 1964, scientists discovered the remains of the earliest humans who made tools in the Olduvai Gorge, Tanzania. Many of the hand bones are very similar to modern human hand bones. Scientists spliced ​​many fragments into a skeleton of a hand. The knuckles at the bottom are particularly strong and the thumb is also very prominent. The shape of this hand already resembles a modern human hand-its thumb is relatively long, so it may be quite flexible. At that time, the hand bones of this early human being 1.8 million years ago aroused strong curiosity. These early humans were no more than 122 cm tall, and scientists called them “capable men.” Although the fossil structure of Homo tooth fossils discovered at the same time is similar to that of the early Australopithecus (apes), there is no controversy about the fact that Homo human hand bones are closer to modern human hand bones.

Eating meat helps human evolution

Simple but sharp stone tools

The hand structure of the Homo sapiens is more complicated than that of the Australopithecus, and the same period pebble tools found in the Olduvai Gorge can also prove that the Homo sapiens has flexible hands. 1.8 million years ago, a capable man living in Olduvai Gorge held a stone hammer in one hand and knocked the stone held by the other hand to create a sharp stone tool. The brains of these canyon residents are only half the size of modern humans. Although their hands are not as dexterous as ours, the hands of capable people are no longer those of the great apes.

With the help of flexible hands and simple but sharp stone tools, capable people have greatly improved their ability to harvest carrion on the prairie. In the vast grasslands, many large mammals that eat grass are often killed by big cats. After these hunters have eaten and left, there is usually a lot of meat left on the remains of the prey. Before the hyenas or vultures come to compete for the corpse, the able men can use sharp stone tools to quickly cut off the remaining meat on the carcass of the prey.

In the early 1990s, two American archaeologists conducted an experiment on the steppes of East Africa. They tried to use simple stone blades made of obsidian (volcanic glass) to cut meat from dozens of animal carcasses (including two elephants). What they didn’t expect was that a humble obsidian blade could easily cut through the hard skin of an elephant. Experimental results proved that the tough muscles, thick tendons and ligaments of these animals seem to be strong, but they are all “vulnerable” in front of stone tools.

Starting to eat meat is a milestone in the evolution of mankind. Prior to this, early great apes were likely to feed mainly on plants. After starting to eat meat, the increase in protein and animal fat intake will inevitably greatly improve the nutritional level of early humans, and help their brain development, thereby enhancing the control of opponents. In this process, our hands are not only used for eating, making tools, throwing or fighting, but also for communication.

From “grabbing” to “gesturing”
There are signs that the evolution of the hand also affects the development of language. For humans, gestures are an important part of expression. They both appear before speaking, and they also appear with speaking. Gestures are used to emphasize what is said and convey emotions, and can be used to express rejection, acceptance, threats, help, sympathy, etc. In the sign language used by the deaf-mute, gestures have almost completely replaced language. Many scientists think. Gestures and sounds have developed together over millions of years. They support and complement each other, creating increasingly complex forms of communication. The children used gestures to express their thoughts before they said their first words.

Hands and language are closely related, and this is also reflected in our relatives-chimpanzees, bonobos, gorillas and orangutans. Although the gestures they can make are very limited, they can also use gestures to communicate. In 2018, British scientists conducted experiments on these animals separately and recorded more than 2,000 gestures made by them. As a result, they found 33 gestures with specific meanings, most of which were simple commands, such as “Give me that!” “Get closer!” “Comb my hair!” or “Don’t do this!” All these gestures are meant to start or stop a specific behavior.

Scientists have discovered that chimpanzees, gorillas, and orangutans not only use most of these gestures, but even use them in the same way. Humans seem to use gestures in a similar way, but how we communicate with them depends more on our social environment, language and culture.

Orangutans can also make gestures.

Human gestures are an important part of expressing intent.

“Speak” with your hands
In the last 20 years, some scientists have been exploring the way to find the origin of language. They compared human behaviors with apes behaviors through various experiments, and found that when apes gestures, they mostly refer to objects that are useful to them at the time, while human gestures are more socially backgrounded, and they often refer to objects that are useful or related to others. Group-related things.

It can be seen that the meaning of gestures begins to revolve around themselves, but in the process of human evolution, gestures gradually have the function of sharing experiences, intentions, benefits, and rules. Scientists believe that communication originated from the use of fingers. For example, an early ape might point to a vulture hovering over a dead animal, or a place with roots (one of the staple foods of humans at that time, sweet potatoes were a kind of roots), or an outlying calf.

At first, directional gestures will help coordinate group activities, such as hunting or babysitting. Later, gestures became more complicated, such as flapping arms to represent a bird, or holding arms to represent a baby. Scientists now believe that sound is added to gesture language to enhance and amplify gesture language. This is consistent with a certain previous view that gestures are basically thoughts or mental images transformed into actions.

Once many Indian tribes spoke different languages, but through “sign language”, one tribe can understand the intentions of another tribe. These pictures are some of the content they express through “sign language.”